Headlights dim

Tiny
CHRISTINEFULLER
  • MEMBER
  • 2006 CHEVROLET TRAILBLAZER
  • 58,000 MILES
Headlights dim at random times and now I've noticed at the same time the heater fan power decreases. I've had the vehicle jumped twice in the past three months before I purchased a new battery. Is this an electrical problem, or alternator, or a relay?
Friday, December 14th, 2012 AT 1:48 AM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
It sounds like the alternator is going bad. When the lights dim, check the alt gauge to see if it is low. With the engine running, it should be producing around 14 volts. With the engine off, it will drop to around 12v.

Let me know what you find.
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Friday, December 14th, 2012 AT 1:53 AM
Tiny
TIMBUCK
  • MEMBER
  • 1 POST
  • 2004 CHEVROLET TRAILBLAZER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 85,000 MILES
The headlights will only come on bright, when you change the dimmer they go off, no dim lights. Thanks Tim
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Monday, May 11th, 2020 AT 12:23 PM (Merged)
Tiny
QUESTIONS32
  • MEMBER
  • 10 POSTS
I am currently experiencing this problem with my 2005 trailblazer and I was wondering if you ever found out what was causing the problem?

I've been to the dealership twice now and they still have no idea so I'd appreciated any information that could help us. Thanks
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Monday, May 11th, 2020 AT 12:23 PM (Merged)
Tiny
RGASTER
  • MEMBER
  • 1 POST
  • 2004 CHEVROLET TRAILBLAZER
  • V6
  • 4WD
  • AUTOMATIC
  • 116,000 MILES
While driving to work my dim headlights went out. The bright lights work fine and the fog lights work fine. Just the dim are out
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Monday, May 11th, 2020 AT 12:23 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check items in pic under hood fuse box. If ok have multi function switch tested and scanned for codes for body module.
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Monday, May 11th, 2020 AT 12:23 PM (Merged)

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